Class: ShellOpts::Args

Inherits:
Array
  • Object
show all
Defined in:
lib/shellopts/args.rb

Overview

Specialization of Array for arguments lists. Args extends Array with a #extract and an #expect method to extract elements from the array. The methods raise a ShellOpts::UserError exception in case of errors

Instance Method Summary collapse

Instance Method Details

#expect(count_or_range, message = nil) ⇒ Object

As #extract except it doesn’t allow negative counts and that the array is expect to be emptied by the operation

#expect raise a ShellOpts::UserError exception if the array is not emptied by the operation



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# File 'lib/shellopts/args.rb', line 45

def expect(count_or_range, message = nil)
  case count_or_range
    when Range
      count_or_range === self.size or inoa(message)
    when Integer
      count_or_range >= 0 or raise ArgumentError, "Count can't be negative"
      count_or_range.abs == self.size or inoa(message)
  end
  extract(count_or_range) # Can't fail
end

#extract(count_or_range, message = nil) ⇒ Object

Remove and return elements from beginning of the array

If count_or_range is a number, that number of elements will be returned. If the count is one, a simple value is returned instead of an array. If the count is negative, the elements will be removed from the end of the array. If count_or_range is a range, the number of elements returned will be in that range. The range can’t contain negative numbers

#extract raise a ShellOpts::UserError exception if there’s is not enough elements in the array to satisfy the request



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# File 'lib/shellopts/args.rb', line 19

def extract(count_or_range, message = nil) 
  case count_or_range
    when Range
      range = count_or_range
      range.min <= self.size or inoa(message)
      n_extract = [self.size, range.max].min
      n_extend = range.max > self.size ? range.max - self.size : 0
      r = self.shift(n_extract) + Array.new(n_extend)
      range.max <= 1 ? r.first : r
    when Integer
      count = count_or_range
      count.abs <= self.size or inoa(message)
      start = count >= 0 ? 0 : size + count
      r = slice!(start, count.abs)
      r.size <= 0 ? nil : (r.size == 1 ? r.first : r)
    else
      raise ArgumentError
  end
end